The Eunice Kennedy Shriver Center conducts an extensive program of research on the causes, treatment, and prevention of mental retardation and developmental disabilities. there are six research divisions: Behavior Analysis, Behavioral Neurology, Biochemistry, Developmental Neurobiology, Neurogenetics and Social Science. The Center also trains professionals and provides services to institutionalized and community-based mentally retarded individuals and their families. The Center is affiliated with the Massachusetts General Hospital, the Harvard Medical School, and several other institutions of higher learning. Numerous collaborations between Shriver scientists and investigators at these other institutions place the Center within the mainstream of biomedical, behavioral, and social science research in the area. This application summarizes progress made in twenty-one years as a Mental Retardation Research Center and outlines the Center's plans for future growth and development. Areas identified for particular emphasis include molecular biology and biomedical/behavioral collaborative studies. The application also describes recent and planned efforts to improve the administrative services and facilities that support the research program. Support is requested for six core units designed to encourage interdisciplinary collaboration and research that is relevant to the missions of the Shriver Center and NICHD. The core units are: Administration, the Animal Facility, Molecular and Cell Biology, Molecular Analysis, Morphological Analysis, and Specialist Services. Each core unit gives high quality, cost-effective service to a number of PHS-funded projects.